1. Field of the Invention
The present invention is broadly concerned with improved roadway crack sealing apparatus which comprises a mobile vehicle with a forward crack sealing assembly including respective fill (e.g., sand) and sealant (e.g., asphalt emulsion or cement) hoppers cooperatively located so that the sealing assembly presents a sighting passageway permitting an apparatus operator to visually locate and follow an elongated roadway crack during forward movement of the vehicle. More particularly, the invention pertains to such apparatus and corresponding methods wherein the sealing assembly is designed to initially apply a particulate fill into the crack, followed by sealant and a top coating of additional fill; preferably, a broom-type finishing assembly is also provided.
2. Description of the Prior Art
Roadway cracks are a constant problem to municipal and state transportation authorities. Unless such cracks are rather promptly filled and sealed as weather permits, they may widen into more significant fissures or potholes. Known roadway crack-filling operations typically involve the use of a truck-mounted kettle or tank containing crack-filling material such as an asphalt emulsion. Applicator brushes, swabs or similar expedients may be dipped into the tank and then onto the roadway defects, as the tank is moved along the road. Alternately, some operations use hoses leading from such a mobile tank to an applicator wand which is operated manually to apply crack-filling material into irregular defects or cracks. After the flowable crack filling material is applied, sand or aggregate is generally applied by a following dump truck and workers who shovel and/or brush the sand or aggregate. Such operations are inherently labor-intensive, requiring a crew of four or more workers. Moreover, production rates are typically low, owing to the fact that the rate is only as fast as the slowest crew member.
A number of specialized repair machines have been proposed in the past, see, e.g., U.S. Pat. Nos. 5,232,306, 5,006,012, 5,263,790, 5,419,654, 4,511,284, 4,676,689 and 894,859. In most cases, such equipment is very expensive because it is entirely purpose-built. Hence, while the equipment may be useful during the season where crack sealing operations are most intense, during some seasonal periods the equipment stands idle. Furthermore, these prior proposals have not adequately provided efficient, high speed and high quality crack sealing as they require labor-intensive crack filling and sealing.
There is accordingly a need in the art for improved roadway crack sealing apparatus which can, if desired, be removably mounted upon a multiple-use vehicle such as a skid steer unit, and which allows efficient roadway crack sealing using only a minimum of crew members.
The present invention overcomes the problems outlined above and provides roadway crack sealing apparatus in the form of a mobile vehicle having a driver compartment with a crack sealing assembly forward of the driver compartment. The sealing assembly includes fill and sealant hoppers each provided with selectively openable outlets for application of fill and sealant onto roadway cracks. The sealing assembly presents spaced side margins and is configured to create an elongated sighting passageway therebetween allowing an operator within the compartment to visually locate and follow an elongated roadway crack during forward movement of the vehicle along a roadway. Furthermore, in preferred forms, a control assembly coupled with the fill and sealant outlets is mounted adjacent the driver compartment so that the driver (or an operator separate from the driver) can continuously manipulate and control the quantity of fill and sealant delivered for crack sealing purposes.
In preferred forms, the fill and sealant hoppers are laterally spaced apart and astride the sighting passageway. The fill hopper advantageously has a pair of spaced, individually controllable outlets, whereas the sealant hopper has a single nozzle-type outlet between the fill hopper outlets. In this way, fill is first deposited into the crack, followed by sealant and then more fill. A drag element is advantageously located proximal to these outlets so that the crack filling materials are properly applied and smoothed during forward motion of the vehicle.
The preferred crack sealing apparatus also includes a finishing assembly which is towed by the vehicle. The finishing assembly has a series of laterally arranged brushes serving to finally brush and finish the crack repair. A rear platform supports a crew member who can manually sweep away any excess fill material and otherwise monitor the progress of the crack sealing operation.
In order to facilitate over the road travel, the forward sealing assembly is equipped with a castered wheel assembly, while the finishing assembly may be moved to an upright, retracted position.
In particularly preferred forms, the apparatus is adapted for connection to a uniloader or skid steer. These types of vehicles are versatile and mobile in all directions and particularly adapted for following cracks which may extend in any direction. The apparatus further comprises one hopper which is adapted to hold a quantity of emulsion and a second hopper which is adapted to hold a quantity of fill material. The emulsion-containing hopper is spaced from the sand-containing hopper such that there is a visible channel between the two hoppers. The fill-containing hopper presents two adjustable doors located near the bottom of the hopper. The doors are laterally spaced apart and have chutes attached thereto for directing the fill material toward cracks in roads. Furthermore, each chute is directed the channel between the two hoppers. At the end of each chute is a second door which meters the amount of sand exiting the chute and deposited in and around the crack being sealed. Although each door is depicted as being manually operable, it is within the realm of the invention to have doors which are operated in other ways including electrically, pneumatically, and hydraulically. Generally, once the hopper is filled with the fill material, each first door leading from the hopper to the chute is opened and left in an open position. This permits the fill to flow from the hopper onto the chute where it is normally retained by each second door which are normally in a closed position. Potential fill materials include manufactured limestone sand, rock chips, gravel, sawdust and wood chips. The use of manufactured limestone sand and sawdust are particularly preferred as the fill materials of choice. In preferred embodiments, the second hopper is also equipped with a castered wheel attached to the bottom of the apparatus. This wheel accommodates some of the weight of the hopper and permits a turning radius approximating zero.
The emulsion-containing hopper includes an outlet leading to a specially designed nozzle located in the channel between the two hoppers. This nozzle is further located between the two chutes of the second hopper. The output of emulsion through the nozzle is controllable by a valve which is operable for varying the emulsion output. Operation of the valve is controlled by the operator of the apparatus. The nozzle is designed to apply emulsion over the top of the crack and onto the sides of the crack, thereby sealing the crack by providing a strip of emulsion which covers the crack and both sides adjacent the crack. The width of this emulsion strip is determined by the width of the nozzle and by a set of squeegees on an emulsion drag. Generally, the nozzle receives emulsion from the emulsion containing hopper. The inflow port of the nozzle is generally round in shape in order to facilitate attachment to a conduit leading to the emulsion tank. The nozzle then presents a channel of diminishing cross sectional area up to the tip (or outflow port) of the nozzle terminating in a slit-shaped outflow port. This slit-shaped outflow port is preferably wider than the cracks to be filled when oriented transversely to the cracks. Such a design permits a strip of emulsion to be applied both to the crack and to the area adjacent the crack. It is contemplated that in some embodiments, the nozzle could be connected to a mobile or swing arm which is controlled by the skid steer operator. Such an arm would provide even greater maneuverability of the nozzle so that cracks can be closely followed and sealed.
The nozzle is also unique in that it is surrounded by a conduit which is in communication with the exhaust port of the skid steer. The connection to the exhaust output serves two purposes; first, the exhaust heats the emulsion immediately prior to its application to the crack, second, the air flow from the exhaust serves to blow away dust and debris from the area adjacent the crack, thereby providing an improved surface for emulsion application.
The apparatus is preferably provided with a series of drags or drag brooms which strike and smooth the sand deposited in the crack. These drag brooms can be located in a variety of places but are preferably located after the first chute but before the nozzle and after the second chute, located behind the skid steer.
In order to facilitate the operation of the apparatus, at least one labor stand is provided. It is preferable to have one labor stand which is adjacent the second hopper such that a worker positioned on the stand has a view of and access to the sand-containing hopper. In this manner, the worker can agitate the fill material therein and thereby ensure that the flow of sand to the chutes is unobstructed. Of course, it is within the scope of this invention to provide a mechanical agitator in the sand-containing hopper rather than using a worker. It is also preferable to locate a second labor stand near the second series of drag brooms which are preferably located behind the skid steer apparatus. The second labor stand is operable for supporting a worker who monitors the crack sealing operation and sweeps away any excess fill material which has been swept away from the sealed crack by the drag brooms. In order to increase safety, the apparatus can be equipped with a safety latch bar to which workers wearing a safety harness or belt can attach themselves.
It is also preferable for the apparatus to have at least one mirror positioned to reflect the channel and the components located therein to the operator of the apparatus. In this manner, the skid steer operator can sight a crack and, using the maneuverability of the skid steer, closely follow the crack contour as it is sealed. A second mirror can be positioned such that the worker located on the labor stand adjacent the sand-containing hopper can monitor the operation of the crack sealer.
In operation, the operator of the skid steer is driving forward and the portion of the apparatus comprising the two hoppers and the channel is located in front of the operator. The operator then sights a crack and positions the apparatus such that the crack is visible through the channel and located adjacent the chutes and nozzle. The second door of the first chute is then opened and sand from the hopper which has already passed through the first door leading to the first chute is deposited into and around the crack. The first series of drag brooms then strikes the level of this deposited sand off level with the sides of the crack. Next, the valve controlling the emulsion application is opened and emulsion is applied over the top of the crack and onto the sides of the crack. The second door at the end of the second chute is then opened allowing sand which has already passed through the first door leading to the second chute to be deposited on top of the strip of emulsion. A second series of drag brooms then strikes this second layer of sand off at a preset level which is either even with the sides of the crack or slightly higher than theses sides. In instances where the sand is left at a higher level by the second series of drag brooms, traffic passing over the sand hump will compress the mixture of sand emulsion into the crack and xe2x80x9cironxe2x80x9d the crack sealing material onto the sides of the crack, thereby providing a greater seal for the crack. Alternatively, if you want to fill cracks, an entirely different nozzle will be employed. This alternative nozzle will deposit a much greater amount of emulsion into the crack. Accordingly, less fill material would be deposited into the crack when using such a nozzle.
As shown in the drawings, the apparatus is positioned such that the channel is located to the right of the skid steer operator and thus is efficient at filling cracks located on the right-hand side of a roadway. Such an apparatus may also fill cracks which are located more toward the center or left-hand side of the roadway, however, in such cases, the apparatus can be designed to more efficiently fill such cracks. For example, the channel could be positioned to the left of the skid steer operator by merely switching the positions of the fill-containing hopper and the emulsion-containing hopper. Alternatively, the apparatus can be built in this manner. In all cases, the operation remains the same regardless of where the channel is positioned. Thus, all such variations in the construction of the apparatus are embraced in the present invention.
It is preferable to use an emulsion which is quick setting and has both adhesive and elastic properties. Preferably, the emulsion used is CRS2 for asphalt or CRS2-P for concrete, either of which can be further modified by the addition of polymer. This elasticity and adhesiveness provides the enhanced ability of this crack sealing material to stick to the sides of the crack and provide a long-lasting seal.
It is preferable in some situations to merely fill or seal the crack with emulsion and not use any fill material. In such cases, the fill-containing hopper is either not used or removed from the apparatus entirely. Of course, an apparatus could be built with just an emulsion-containing hopper, however, for ease of illustration and convenience of use, it is preferable for the apparatus to include both hoppers.
Other useful accessories for the apparatus include a spray mister, a heating or insulating mechanism for the emulsion tank, a substrate heater, and a cover for the fill-containing hopper. Preferably, the spray mister would be located between the first hopper door and the emulsion nozzle which can provide a fine spray of soapy water (which improves the performance of the emulsion) in front of the emulsion nozzle to dampen the dust and surface of the road thereby permitting the emulsion to soak through the dust and in through the cracks and adhere to the road. The heating or insulating mechanism for the emulsion tank would permit emulsion to be stored in the tank for greater periods of time prior to the emulsion setting. For example, an electric heater or electric blanket could be used in conjunction with the emulsion tank. In the case of applications using hot-pour tar, the heating mechanism would preferably comprise burners adapted to heat the oil, melt the tar, and to prevent the same from setting in the tank or dispensing apparatus. The substrate heater would typically be located in front of the emulsion nozzle and could be used during wet or cold weather conditions to heat and at least partially dry the sidewalls of the crack, thereby improving the conditions for emulsion adhesion. When using wood chips or sawdust as the fill material, the fill-containing hopper may be equipped with a removable or openable top. Such a top would keep the wood chips and saw dust dry during inclement weather. Preferably the top would be adapted through arching or the like such that a laborer could continue to ensure consistent movement of the material into the chutes when the hopper was not equipped with a mechanical agitator.
Advantageously, the preferred apparatus is designed such that the crack sealer may be driven up to the back of a dump truck with either a center or under gate attachment thereby allowing the dump truck to deposit fill material directly into the sand-containing hopper. Therefore, no additional labor is required to fill the hopper with sand.
Of course, the apparatus can be manufactured to accommodate any amount of fill material and emulsion. For example, a 2000 pound lift skid steer may be attached to an apparatus holding about 600 pounds of fill material and 50 gallons of emulsion. Larger or smaller vehicles or skid steers which hold larger or smaller amounts of crack sealing materials may be employed as desired.
Thus the present invention overcomes the problems in the field and provides an efficient, easily operable and maintainable crack sealing apparatus. Using the present invention, 31.34 miles of road were repaired in 95.5 hours using a six man crew (approximately 0.33 miles of road/hour). Using the previously known conventional crack sealing methods, 3.8 miles of roads were repaired in 120 hours using another six man crew (approximately 0.032 miles of road/hour). Thus the present invention provided a ten-fold increase in efficiency. Furthermore, using the present invention, the sealed cracks should last longer and be more durable due to the application of emulsion in the crack and along the sides of the crack.